Polishing system and dressing device thereof

ABSTRACT

Provided is a dressing device for a carrier. The dressing device comprises a dresser, a swing arm, a base and at least one damper. A first end and a second end of the swing arm are coupled to the dresser and the base, respectively, and the at least one damper is disposed inside the swing arm. Any axial vibration of the dresser or the swing arm during dressing for the carrier can be compensated or attenuated by the damper in an active manner properly, so as to make the surface of the carrier flatter and more uniform, which not only improves a removal rate of material and a polishing result of the surface in the subsequent chemical mechanical planarization process, but also prolongs the service life of the carrier. The present disclosure further relates to a polishing system for dressing the carrier by using the said dressing device.

FIELD OF THE INVENTION

The present disclosure relates to an application of Chemical-Mechanical Planarization/Polishing process, and more particularly, to a dressing device for a carrier.

BACKGROUND

Chemical-Mechanical Planarization/Polishing (CMP) process is a common process used in semiconductor industries for manufacturing silicon wafers with smooth and flat surfaces, in which the most essential performance indicators are uniformity of polished wafers, smoothness of IC circuits, removal rate of material, service life for CMP consumptions, etc.

CMP process can be used for a comprehensive planarization process, in which a wafer or a substrate is rotated and pressed down by a holder (such as a grinding head) to a surface of the carrier (e.g., polishing pad) which is self-rotated driven by a rotating platform, and a slurry with chemical properties is supplied on the surface of the carrier to generate a passivation layer with a soft structural property on the surface of the wafer or the substrate, and then it cooperates with abrasives carried on the surface of the carrier to remove the passivation layer by mechanical force, thereby to obtain flat wafers or substrates. CMP process in a long term will cause debris and abrasive particles of wafers or substrates to block holes of the carrier or to passivate the surface of the carrier, so as to reduce the removal rate of material of wafers or substrates. Hence, the carrier must be dressed to improve its working performance again to maintain the qualities of wafers or substrates.

However, self-vibrations of CMP process machines, oscillation over the surface of the carrier by a dresser, rotation of the carrier, self-rotation of a dresser body, and non-uniformity of the carrier itself may cause shaking and vibration of the dressers (e.g., diamond dresser) during the process for dressing the carrier, but for the current CMP process machines of the prior art, it does not process effective compensation or attenuating the vibration of the dresser during dressing, which will affect the flatness of dressed surfaces of the carrier after dressing and the characteristics of the surface microstructure, even which will cause poor removal rate of material of wafers in the subsequent CMP process and the poor polishing effects to the surfaces thereof. Especially in the recent semiconductor advanced process, the above problems become more serious and cannot be ignored.

As a result, how to propose an effective solution to the above problems, and to improve the dressing performance of the dresser and to prolong the service life of the carrier are essential issues to be solved in this technical field.

SUMMARY

In order to solve the above problems, the present disclosure provides a dressing device, which comprises: a dresser for dressing a surface of a carrier; a swing arm having a first end and a second end opposed to the first end, wherein the first end is coupled to the dresser; a base coupled to the second end and configured to make the swing arm and the dresser oscillate over the surface of the carrier; and at least one damper disposed inside the swing arm to adjust vibration of the dresser or the swing arm during oscillation.

In some embodiments of this disclosure, the at least one damper is disposed adjacent to the first end.

In some embodiments of this disclosure, the at least one damper comprises a longitudinal axis damper, a lateral axis damper, or a combination thereof, wherein the longitudinal axis damper is used for adjusting the vibration of the dresser or the swing arm perpendicular to the surface of the carrier during the oscillation, and the lateral axis damper is used for adjusting the vibration of the dresser or the swing arm parallel to the surface of the carrier during the oscillation. In some embodiments of this disclosure, the at least one damper comprises a lateral axis damper and a longitudinal axis damper.

In some embodiments of this disclosure, the at least one damper comprises a tuned mass damper. In some embodiments of this disclosure, the tuned mass damper is an active tuned mass damper. In some embodiments of this disclosure, the active tuned mass damper comprises: a sensor for sensing a real-time motion signal corresponding to the vibration of the dresser or the swing arm during the oscillation; a control unit configured to calculate a load of the vibration according to the real-time motion signal and generate a control signal based on the load; and an actuator configured to adjust a damping coefficient of the active tuned mass damper according to the control signal, thereby make the active tuned mass damper outputs an active control force of the load to reduce the vibration.

In some embodiments of this disclosure, the active tuned mass damper comprises: a piezoelectric sensor for sensing a real-time accelerating signal corresponding to the vibration of the dresser or the swing arm during the oscillation, a control unit configured to calculate a load of the vibration according to the real-time accelerating signal and generate a control signal based on the load; and an piezoelectric actuator configured to adjust a damping coefficient of the active tuned mass damper according to the control signal, thereby making the active tuned mass damper outputs an active control force of the load to reduce the vibration. In some embodiments, the piezoelectric actuator is configured to output the active control force through a damping frequency for reducing the vibration.

In some embodiments of this disclosure, the base comprises a rotating shaft which rotated by an actuator to drive the swinging arm and the dresser to oscillate over the surface of the carrier.

The present disclosure further provides a polishing system, which comprises: a rotatable platform; a carrier disposed on an upper surface of the rotatable platform to carry a wafer or a substrate; a holder (or retainer) disposed over the carrier to retain the wafer or the substrate on a surface of the carrier to process polishing; a dressing device of the present disclosure is disposed over the carrier to dress the surface of the carrier.

In some embodiments of this disclosure, further comprises a nozzle disposed over the carrier to supply a slurry with abrasives to the surface of the carrier.

To sum up, the polishing system and dressing device thereof of the present disclosure are mainly disposed at least one damper inside the swing arm of the dressing device to properly compensate or attenuate the vibration of the dresser or the swing arm from any axis during dressing for the carrier, such that the expected roughness, flatness, uniformity, and microstructure of the surface of the carrier can be achieved after dressing, thereby not only improving removal rate of material and polishing result of the surface in the subsequent chemical-mechanical planarization process, but also prolonging service life of the carrier.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic view depicting components of a polishing system in accordance with at least one embodiment of the present disclosure.

FIG. 2 is a side view depicting a dressing device with a wafer in accordance with at least one embodiment of the present disclosure.

FIG. 3A is a side view depicting the dressing device in accordance with at least one embodiment of the present disclosure.

FIG. 3B is a top view depicting the dressing device of FIG. 3A.

FIG. 4 is a schematic view depicting an implementation of the dressing device in accordance with at least one embodiment of the present disclosure.

FIG. 5 is a schematic view depicting an implementation of the dressing device in accordance with at least one embodiment of the present disclosure.

DETAILED DESCRIPTION

Implementations of the present disclosure are described below by specific embodiments. One of ordinary skill in the art can readily appreciate other advantages and technical effects of the present disclosure upon reading the content of this specification. However, specific embodiments of the content of this specification are not meant to limit the present disclosure, the present disclosure can also be implemented or applied by other different implementations, various details contained in the content of this specification in accordance with different aspects and applications can also be given different changes or modifications without departing from the scope of the present disclosure.

It should be noted that the structures, ratios, sizes and the like shown in the drawings appended to this specification are provided in conjunction with the disclosure of this specification for those skilled in the art to read and understand, rather than to limit the implementable scope of the present disclosure, thus any modifications to the structures, changes to ratio relationships, or adjustments to sizes, are to be construed as falling within the range covered by the technical content disclosed herein to the extent of not causing changes in the technical effects created and the objectives achieved by the present disclosure.

It should be noted that terms such as “comprise”, “contain”, “having” or “with” specific components recited herein, unless further illustration, otherwise it can further comprise other components, group compounds, structures, regions, parts, devices, systems, steps, connection relationships and the like components, rather than excluding aforementioned other components.

It should be noted that sequential terms such as “first” or “second” recited herein merely describe or differentiate components, group compounds, structures, regions, parts, devices, systems, and the like components in convenience, rather than to limit the implementable scope of the present disclosure, either to limit the spatial sequence of the aforementioned components. Furthermore, unless further explicit illustration, otherwise the singular-form terms “one” and “the” herein also include the plural-form, and the term “or” herein can be used interchangeably with the term “and/or.”

It should be noted that the terms “on”, “over”, “parallel”, and “vertical” and the like terms with spatial relativity herein merely clarify the relative position and relationship between one component or feature and other component or feature in specific embodiments of the present disclosure in convenience, rather than to limit the implementable scope of the present disclosure, in means that adjustments, interchanges, and modifications to relative locations and relationships, without changes in the substantial technical content of the present disclosure, should also to be regarded as within the scope in which the present disclosure can be implemented. In addition, the term “parallel” herein refers to essentially parallel, including situations where the angle between two components, two axes, or two planes is minus 10 degrees to plus 10 degrees at 0 degree, such as negative 5 degrees to positive 5 degrees; the term “vertical” herein refers to essentially vertical, including situations where the angle between two components, two axes, or two planes is minus 10 degrees to plus 10 degrees at 90 degrees, such as 85 degrees to 95 degrees.

It should be noted that the term “coupling” herein refers to a plurality of components directly or indirectly combined together by mechanical, chemical, electrical, magnetic, or a combination of two or more thereof, the term “direct coupling” refers to a direct contact between a plurality of components combined together while the term “indirect coupling” refers to that a plurality of components are joined together by at least one coupler. The means to achieve the “coupling” herein includes but not limited to tightly or gapped connected, pivoted, connected, stitched, joined, adhered, embedded, screwed, snapped, stapled, clipped, attached, threaded, clamped, placed, integrally molded, or a combination of two or more thereof. The term “coupler” herein refers to a component that can be capable of achieving the aforementioned mean of “coupling”.

It should be noted that the term “actuator” herein refers to power devices which drive movements of objects, device, or systems by conversion various energy or power sources into mechanical kinetic energy. The actuator has different implementations in accordance with different types of the energy or power sources. In at least one embodiment of this disclosure, the actuator comprises but not limited to a pneumatic actuator (e.g., a pneumatic cylinder), a hydraulic actuator (e.g., a hydraulic cylinder), an electrical actuator (e.g., DC motor, AC motor, or step motor), an electromechanical mixed actuator (e.g., an electromagnetic valve). In at least one embodiment of this disclosure, the actuator is used to drive objects, devices, or systems for rotations. In at least one embodiment of this disclosure, the actuator is a piezoelectric actuator.

Referring to FIG. 1 , a dressing device 22 in accordance with the present disclosure is applicable to a polishing system 2 of polishing process (e.g., a CMP process). In at least one embodiment of this disclosure, the polishing system 2 comprises a rotatable platform 20, a carrier 21 (e.g., a polishing pad or a grinding with polishing disk with or without abrasives, a polishing pad, a grinding with polishing disk, or a disk, or the like with or without grooves), a dressing device 22, a holder 23 (e.g., a grinding head), and a nozzle 24. The carrier 21 is disposed on a top surface of the rotatable platform 20 to carry a wafer 25, and is rotated with the rotation of the rotatable platform 20; the holder 23 is disposed over the carrier 21 to retain (e.g., absorb) the wafer 25, and to rotate with press down the wafer 25 to the surface of the carrier 21 to process polishing; the nozzle 24 is disposed over the carrier 21 to supply abrasives and chemical slurry to the top surface of the carrier 21, to facilitate the carrier 21 for polishing the surface of the wafer 25. In at least one embodiment of this disclosure, the rotatable platform 20 or the holder 23 is configured to be rotated through control of an actuator (not shown).

In at least one embodiment of this disclosure, the carrier 21 is a soft and flexible elastic pad, which cannot process material removal by means of inherently fixed depth of cut (i.e., dressing), so the process of grinding and dressing are performed by controlling the force. In order to address the carrier 21 to the best effect without affecting (or optimizing) the removal rate of material and polishing result of the surface of the subsequent wafer 25 or substrate, the dressing device 22 in at least one embodiment of the present disclosure is configured to not only perform the dressing works such as conditioning, cleaning, regenerating roughness and the like of the carrier 21 during the polishing process, but also adjusting the vibration during the dressing works.

FIG. 2 of the present application is an implementation aspect presenting the dressing device 22 of the polishing system 2 disposed on the carrier 21 in a side view, each of the component outside the dressing device 22 and the carrier 21 is mentioned above and will not be described here again. In at least one embodiment of this disclosure, the dressing device 22 comprises a base 221, a swing arm 222, and a dresser 223. The swing arm 222 includes a first end 2221 and a second end 2222 opposed to the first end 2221, wherein the first end 2221 is coupled with the dresser 223, the second end 2222 is coupled with the base 221. In at least one embodiment of this disclosure, the base 221 is disposed outside of the rotatable platform 20. In at least one embodiment of this disclosure, the base 221 comprises a rotating shaft pivoted by controlling of an actuator (not shown), which is configured to act as a supporting point to drive the swing arm 222 to oscillate (e.g., sweep back and forth) over the carrier 21, and further to drive the dresser 223 to oscillate (e.g., sweep back and forth) over the surface of the carrier 21 to process dressing. In at least one embodiment of this disclosure, the dresser 223 is a diamond dresser, which can be suspended over the carrier 21 and be pressed down as needed (e.g., when approaching to the place to be dressed), and the surface of the carrier 21 is re-textured by means of self-friction of the bottom surface of the diamond abrasives.

In at least one embodiment of this disclosure, the dressing device 22 further comprises at least one damper 30 configured to adjust (e.g., compensate or attenuate) the vibration of the polishing system itself during the dressing for the carrier 21, the self-rotation of the carrier 21 on the rotatable platform 20 (e.g., rotating around the center of the rotatable platform 20 as a shaft), the self-rotation and press-down of the dresser 223 during the dressing of the carrier 21, self-oscillation (e.g., sweep back and forth) of the swing arm 222, or the vibration (e.g., vibration or shaking) generated under the situation with unevenness of the surface of the carrier 21. In at least one embodiment of this disclosure, at least one damper 30 is disposed inside the swing arm 222, more preferably, at least one damper 30 is disposed on a first end 2221 inside the swing arm 222. In at least one preferred embodiment of this disclosure, at least one damper 30 is disposed on a first end 2221 inside the swing arm 222 (i.e., the place over the dresser 223 within swing arm 222), as the first end 2221 being the supporting point is far from the base 221, which leads the greatest longitudinal and lateral amplitudes of the swing arm 222 during the oscillation, thus the damper 30 disposed on the first end 2221 can maximize the effect for the reduction of the vibration. In other embodiments of this disclosure, the set position of at least one damper 30 can be disposed on other positions of the swing arm 222 or on the base 221 based on the configuration of the dressing device 22 and its actual requirements for the reduction of the vibration. In at least one preferable embodiment of this disclosure, at least one damper 30 can be installed on the swing arm 222 by attaching to meet the requirements for users to perform dressing or displacement at any time.

The term “damper” herein refers to a component, a device, or a system to reduce the vibration by damping characteristics.

In at least one embodiment of this disclosure, the dressing device 22 comprises at least one axis damper; more preferably, the dressing device 22 comprises a plurality of axes dampers to adjust (e.g., compensate of attenuate) vibrations generated from different axes during the dressing work. The term “axis damper” herein refers to a damper with at least one degree of freedom provided on an axis direction. FIGS. 3A and 3B show the dressing device 22 of an embodiment of this disclosure, which comprises a longitudinal axis damper 31 and a lateral axis damper 32, and the rest of the components are mentioned above and will not be described here again.

FIG. 3A shows that the longitudinal axis damper 31 is disposed on the first end 2221 of the swing arm 222 in parallel to the pressing-down direction of the dresser 223 (i.e., the direction perpendicular to the surface of the carrier 21) to adjust (e.g., compensate or attenuate) the forced vibration perpendicular to the dresser 223. Therefore, when pressing down the dresser 223 to the surface of the carrier 21 for dressing, the longitudinal axis damper 31 can reduce the unevenness of the surface of the carrier 21 or reduce the longitudinal vibration (relative to the surface of the carrier 21) caused by the pressing-down of the dresser 223.

FIG. 3B shows that the lateral axis damper 32 is disposed at the first end 2221 of the swing arm 222 in parallel to the vibration direction (i.e., the direction parallel to the surface of the carrier 21) of the swing arm 222 to adjust (e.g., compensate or attenuate) the forced vibration parallel to the dresser 223. Therefore, when the dresser 223 processes dressing on the surface of the carrier 21, the lateral axis damper 32 can reduce the lateral vibrations caused by the situations of the self-rotated grinding of the dresser 223, self-rotation of the carrier 21, the vibration of the swing arm 222, and the unevenness of the surface of the carrier 21.

By means of the cooperation effect of the aforementioned longitudinal axis damper 31 and lateral axis damper 32, it can be effectively reduced the vibration interference of the swing arm 222 or the dresser 223 during the dressing work, such that the expected roughness, flatness, and uniformity of the surface of the carrier 21 can be achieved after the dressing, and service life of the carrier 21 can be prolonged. In another embodiments of this disclosure, in addition to the aforementioned longitudinal axis damper 31 and lateral axis damper 32, the dressing device 22 further comprises dampers on other axes to adjust vibrations from other axes. In other embodiments of this disclosure, a single axis damper can also concurrently adjust vibrations from different axes.

In at least one embodiment of this disclosure, the dressing device 22 comprises a passive damper, an active damper, or a combination thereof.

The term “passive damper” herein refers to a damper 30 without active control force. In at least one embodiment of this disclosure, the passive damper comprises an elastic component (e.g., spring or elastic material) and a damping mass m (e.g., mass block), and the elastic component is coupled with the damping mass m for reducing the vibration during the dressing.

The term “active damper” herein refers to a damper 30 with active control force. In at least one embodiment of this disclosure, the active damper including using for a sensor (e.g., position sensor, speed sensor, accelerometer, or a combination of two of more thereof), a control unit (e.g., control circuit or controller), and an actuator (e.g., piezoelectric actuator), wherein the sensor is configured to detect a motion signal (e.g., position, speed, acceleration, or a combination of two or more thereof) corresponding to the vibration during the dressing, the control unit is configured to drive the actuator for reducing the vibration in accordance with a control signal generated from the motion signal. In some of embodiments of this disclosure, the actuator adjusts the damping coefficient of the active damper for outputting the active control force of the active damper to reduce the vibration. In another embodiment of this disclosure, the active damper comprises a damping mass m (e.g., mass block), the actuator is configured to reduce the vibration by changing the position or the motion of the damping mass m.

In at least one embodiment of this disclosure, the damper 30 has a converter (not shown) to convert vibrating mechanical energy into electrical energy or heat during the dressing, thereby reducing energy of the vibration and achieving the effect of reducing the vibration.

In at least one embodiment of this disclosure, the damper 30 can be a tuned mass damper (TMD), when the vibration frequency of the tuned mass damper matches the vibration frequency of the dressing, the generated energy from the vibration will be transferred to the tuned mass damper to achieve the effect of reducing the vibration. The tuned mass damper comprises a passive tuned mass damper (PTMD) and an active tuned mass damper (ATMD), in which the vibrating frequency and the damping value of the passive tuned mass damper is fixed for reducing the vibration with fixed frequency while the vibrating frequency and the damping value of the active tuned mass damper can be adjusted in accordance with real-time changes of the vibration, thereby it can adapt to various vibration of the dressing. In at least one embodiment of this disclosure, the dressing devise 22 comprises a passive tuned mass damper, an active tuned mass damper, or a combination thereof. In some of embodiments of this disclosure, the longitudinal axis damper 31 and the lateral axis damper 32 are both active tuned mass dampers. In some of embodiments of this disclosure, the active tuned mass damper is a phase control active tuned mass damper (PCATMD).

FIG. 4 shows a specific embodiment of at least one damper 30 (including a longitudinal axis damper 31 and a lateral axis damper 32) of this disclosure, the damper is an active tuned mass damper, and comprises at least one piezoelectric sensor 301, control circuit 302, and piezoelectric actuator 303, etc.

In FIG. 4 of the present application, the piezoelectric sensor 301 is configured to sense a real-time accelerating signal corresponding to the vibration of the aforementioned dressing, and the real-time accelerating signal is configured to determine the axis of the vibration and to subsequently calculate the load of the vibration. And then, the real-time accelerating signal is transferred to the control circuit 302 for calculating the load of the vibration. The load of the vibration acts as a reference to control the active control force generated from the damper 30 to reduce the vibration, the calculation thereof is described in FIG. 5 of the present disclosure in detail and related information is described as follows. Lastly, the control circuit 302 generates control signals in accordance with the load of the calculated vibration and transmits them to the piezoelectric actuator 303, thereby at least one damper 30 is performed the corresponding adjustment with respect to the vibration, the calculation thereof is described in FIG. 5 of the present application in detail and related information is described as follows. Accordingly, as to the vibration of the swing arm 222 or the dresser 223 during the dressing, the piezoelectric actuator 303 adjusts at least one damping coefficient of the damper 30, such that at least one damper 30 outputs the active control force enough to resist or eliminate (compensate or attenuate) the vibration of the load with the damping frequency corresponding to the vibration, whereby the vibration can be controlled within the predetermined range to achieve the best effect for reducing the vibration.

FIG. 5 further depicts a dressing device 22 suffered from the vibration during the aforementioned dressing, which is related to physical properties of at least one damper 30, and calculates, by the aforementioned control circuit 302, the load that the dresser 223 may be suffered from the vibration and generates the calculation process corresponding to the control signals can be understood with the following.

At first, the real-time acceleration of the vibration sensed by the piezoelectric sensor 301 can be converted into load (e.g., by using a general force conversion equation) by controlling the circuit 302, as shown by f(t) in FIG. 5 of the present disclosure, the direction instructed by the corresponding arrow refers to any axis of the vibration.

And then, the load f(t) to be adjusted is represented as a dynamic equation by the following mathematical equation:

m ₁ {umlaut over (x)} ₁+(c ₁ +c ₂){dot over (x)} ₁ −c ₂ {dot over (x)} ₂+(k ₁ +k ₂)x ₁ −k ₂ x ₂ =f(t),

m ₂ {umlaut over (x)} ₂ +c ₂({dot over (x)} ₂ −{dot over (x)} ₁)+k ₂(x ₂ −x ₁)=0  [Mathematical equation 1]

-   -   wherein m₁ represents the mass of the dressing device 22; m₂         represents the mass of the damper 30; c₁ represents the damping         coefficient of the dressing device 22; c₂ represents the damping         coefficient of the damper 30; k₁ represents the elastic         coefficient of the dressing device 22; k₂ represents the elastic         coefficient of the damper 30; and x₁, {dot over (x)}₁, {umlaut         over (x)}₁ respectively represent vibration responses of the         dressing device 22 as a function of displacement, velocity, and         acceleration with respect to time t; and x₂, {dot over (x)}₂,         {umlaut over (x)}₂ respectively represent vibration responses of         the damper 30 as a function of displacement, velocity, and         acceleration with respect to time t.

Then converting the aforementioned load f(t) into linear time-invariant function by Laplace transformation, so as to express the active control force f(s) which is outputted by the piezoelectric actuator 303 with the following mathematical equation:

[m ₁ s ²+(c ₁ +c ₂)s+(k ₁ +k ₂)]X ₁−(c ₂ s+k ₂)X ₂ =f(s)

(m ₂ s ² +c ₂ s+k ₂)X ₂−(c ₂ s+k ₂)X ₁=0  [Mathematical equation 2]

wherein the composition of the mathematical equation 2 is similar to the mathematical equation 1, the differences between them are that the aforementioned x₁, {dot over (x)}₁, {umlaut over (x)}₁ representing the vibration responses of the dressing device 22 are represented as a set X₁, and the aforementioned x₂, {dot over (x)}₂, {umlaut over (x)}₂ representing the vibration responses of the damper 30 are represented as a set X₂, and the other variants are sorted out accordingly.

Subsequently, combine the two equations of Mathematical equation 2 and sort it out by the following mathematical equation:

$\begin{matrix} {{{{\left( {s^{2} + {2\omega_{1}\xi_{1}s} + \omega_{1}^{2}} \right)X_{1}} + {\mu s^{2}X_{2}}} = \frac{{f(s)}\lambda^{2}\mu\omega_{1}^{2}}{k_{2}}},} & \left\lbrack {{Mathematical}{equation}3} \right\rbrack \end{matrix}$

wherein

$\omega_{1} = \sqrt{\frac{k_{1}}{m_{1}}}$

represents the fixed frequency of the dressing device 22 (without damping);

$\xi_{1} = \frac{c_{1}}{2m_{1}\omega_{1}}$

represents the damping ratio of the dressing device 22;

$\mu = \frac{m_{2}}{m_{1}}$

represents the mass ratio of the dresser 30 to the dressing device 22; and

$\lambda = \frac{\omega_{1}}{\omega_{2}}$

represents the basic frequency ratio of the dresser 30 to the dressing device 22.

The frequency characteristics of the damper 30 may be figured out by the control circuit 302 in accordance with the calculation result of the aforementioned mathematical equation 3, so as to determine how to adjust the damping coefficient of the damper 30, thereby to properly output active control force f(s) for adjustment when suffering from the vibration.

Finally, evacuate the adjustment content required for the damper 30 to output the predetermined active control force f(s) based on the system transfer function H(s) of the damper 30 calculated by the aforementioned mathematical equation 3 (including to output the specific damping frequencies of the active control force f(s) and the adjustment range of the required damping coefficient), which represents by the following mathematical equation:

$\begin{matrix} {{H(s)} = \frac{1}{\begin{matrix} {{m_{1}s^{2}} + {\left( {c_{1} + c_{2}} \right)s} + \left( {k_{1} + k_{2}} \right) -} \\ \left( {\left( {{c_{2}s} + k_{2}} \right)^{2}/\left( {{m_{2}s^{2}} + {c_{2}s} + k_{2}} \right)} \right) \end{matrix}}} & \left\lbrack {{Mathematical}{equation}4} \right\rbrack \end{matrix}$

As a result, the control circuit 302 can generate control signals in accordance with the calculation results of the aforementioned mathematical equation 3 and mathematical equation 4, and also control the piezoelectric controller 303 based on the system transferred function H(s) for controlling the damper 30 to adjust its damping coefficient and output the active control force f(s) by in response to damping frequency of the vibration, so as to compensate or attenuate the dresser 223 suffered from the vibration during the dressing to achieve the expected effect for reducing the vibration.

To sum up, the polishing system and dressing device thereof of the present disclosure are mainly disposed at least one damper inside the swing arm of the dressing device, the damper can properly compensate or attenuate the vibration of any axis in the dresser or the swing arm during the dressing for the carrier in an active manner, so the expected roughness, flatness, uniformity, and microstructure of the surface of the carrier after the dressing can be achieved, thereby not only improves removal rate of material and polishing result of the surface in the subsequent chemical-mechanical planarization process, but also prolongs service life of the carrier. 

What is claimed is:
 1. A dressing device, comprising: a dresser for dressing a surface of a carrier; a swing arm having a first end and a second end opposed to the first end, wherein the first end is coupled to the dresser; a base coupled to the second end and configured to make the swing arm and the dresser oscillate over the surface of the carrier; and at least one damper disposed inside the swing arm to adjust vibration of the dresser or the swing arm during oscillation.
 2. The dressing device of claim 1, wherein the at least one damper is disposed adjacent to the first end.
 3. The dressing device of claim 1, wherein the at least one damper comprises a longitudinal axis damper for adjusting the vibration perpendicular to the surface of the carrier, a lateral axis damper for adjusting the vibration parallel to the surface of the carrier, or a combination thereof.
 4. The dressing device of claim 1, wherein the at least one damper comprises a tuned mass damper.
 5. The dressing device of claim 4, wherein the tuned mass damper is an active tuned mass damper.
 6. The dressing device of claim 5, wherein the active tuned mass damper comprises: a sensor for sensing a real-time motion signal corresponding to the vibration; a control unit configured to calculate a load of the vibration according to the real-time motion signal and generate a control signal according to the load; and an actuator configured to adjust a damping coefficient of the active tuned mass damper according to the control signal, thereby making the active tuned mass damper outputs an active control force of the load to reduce the vibration.
 7. The dressing device of claim 6, wherein the sensor is a piezoelectric sensor, the real-time motion signal is a real-time accelerating signal, the control unit is a control circuit, the actuator is a piezoelectric actuator, and the piezoelectric actuator is configured to output the active control force through a damping frequency for reducing the vibration.
 8. The dressing device of claim 1, wherein the base comprises a rotating shaft rotated by an actuator to drive the swinging arm and the dresser to oscillate over the carrier.
 9. A polishing system comprising: a rotatable platform; a carrier disposed on an upper surface of the rotatable platform to carry a wafer or a substrate; a holder disposed over the carrier to retain the wafer on a surface of the carrier to process polishing; a dressing device of claim 1, which is disposed over the carrier to dress the surface of the carrier.
 10. The polishing system of claim 9, further comprising: a nozzle disposed over the carrier to supply a slurry including abrasives to the surface of the carrier. 